As wireless networks evolve and grow, there are ongoing challenges in providing high-quality service to increasing numbers of wireless devices or user equipment (UE) in various coverage areas of a wireless network. One approach to improving service quality and coverage is to designate a wireless device as a relay node or relay UE for relaying communication between a base station or donor access node and an end-user wireless device. Because relay wireless devices exhibit significantly higher activity levels than end-user devices, the introduction of wireless relay devices can contribute to interference, such as cross talk or co-channel interference, in neighboring access nodes. The amount of interference may increase with an increase in number of wireless relay devices attached to the donor access node.
One general approach to mitigating interference is to offload devices from one frequency band class in which the interference is occurring to another frequency band class with less potential for interference. For example, in wireless networks that deploy multiple frequency bands within a single geographic area, such as co-located cells or access nodes, inter-frequency handovers are used to offload end-user wireless devices from a congested frequency band to a non-congested frequency band. Typically, inter-frequency handovers are triggered based on radiofrequency (RF) strength of signals transmitted from one or more access nodes. For example, in a long-term evolution (LTE) system, signal level parameters including thresholds are transmitted to end-user wireless devices in system information block (SIB) messages, and measurement events such as A2, A3 and A5 events can trigger a handover request from an end-user wireless devices based on whether a signal level of an access node exceeds or falls below a threshold.
Overview
Exemplary embodiments described herein include methods, systems, and devices for dynamic handover threshold adjustment based on a number of relay wireless devices attached to a neighboring cell. A method of allocating frequency bands of an access node includes determining a number of relay wireless devices attached to a donor access node neighboring the access node and transmitting to the access node information related to the number of relay wireless devices attached to the donor access node. An inter-frequency handover threshold of the access node is altered based at least in part on the information related to the number of relay wireless devices attached to the donor access node.
A method of allocating frequency bands of an access node among user devices includes determining a number of wireless relay devices attached to a donor access node neighboring the access node, transmitting to the access node information related to the number of wireless relay devices attached to the donor access node, comparing a radio characteristic of the access node with a threshold radio characteristic based at least in part on the information related to the number of wireless relay devices attached to the donor access node, and offloading a relay wireless device from a first frequency band class of the access node to a second frequency band class of the access node based on a comparison of the radio characteristic and the threshold radio characteristic.
A system includes an access node, a neighboring donor access node, and a processor associated with the access node. The processor is configured to receive information related to a number of relay wireless devices attached to the donor access node, alter a threshold radio characteristic based at least in part on the information related to the number of relay wireless devices attached to the donor access node, and offload a user device from a first frequency band class of the access node to a second frequency band class of the access node based on a comparison of the radio characteristic and the threshold radio characteristic.